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PostPosted: Wed Jun 26, 2013 6:35 pm 
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Joined: Fri Mar 23, 2012 7:58 pm
Posts: 154
Hi guys, it's been a hell of a time since I posted here on the forum. I have a problem with my Benjamin Sheridan NP XL. While disassembling it for maintenance I noticed that the wheel on the lever assembly was broken and my cylinder badly scratch from breaking the barrel. I ordered and installed a new lever assembly on a spare new cylinder and... it's still is scratching the cylinder, even with the new lever assembly with the wheel. If can't understand why... I'm guessing that the lever assembly is not doing it's job to roll on the stock. Meanwhile I put 2 layer of smooth surface tape with grease between. It work flawlessly but look like hell. Could you help me? Thx!

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PostPosted: Wed Jun 26, 2013 11:02 pm 
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Joined: Sun Jan 29, 2012 7:31 pm
Posts: 696
Location: Halifax, NS
Last pic - see that little slot to the left of the tape ?
There is supposed to be a little plastic door frame piece that goes on & sits proud & cause it does so, it takes up the friction between arm & tube.
Just to experiment & cause this little plastic piece is far from permanent; a while back I had taken out the door frame & replaced it with a small piece of insulated clothesline. Tied it around the slot then twisted the ends together & squished em out of the way to a side - worked flawlessly but I installed the plastic bit back.
The only time really it seems to fall out is when stock is separate from action...you can try a heavy duty zip tie & snip off the extra. IF you still have the stock plastic bit - applying a lil moly right on the slot helps keep the plastic pc in place as you assemble the gun.
About the plastic roller; ask someone to cock your gun slowly as you keep an eye on this link rod .. it SHOULD travel straight down the tube, (Crosman design encourages side to side play in the cocking arm/link assembly & one of the culprits is the joint on the arm/link that is just past the slot that is to the right of the tape) if it is canting to one side during cocking stroke - it might just cause the roller to ride off the inside channel in your stock causing it to break off. If your cocking lever is in fact canting far enough toward one side. Relieving compression on the stroke may help a little, one may do this by removing the washers or spacers or both behind the piston if you have 2 of each, you don't want to remove all washers & spacers as they do assist with possible twist & torque during cocking & firing. I tried installing washers on both sides of the cocking arm before pushing the pin through when installing to underside of barrel, it did reduce the side to side play a bit & also helped with the cocking arm staying (more) straight...but workarounds are no match for better design.
If you keep cocking the gun without fixing this .. your tube will gall badly for sure.
Let us know how you make out.

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PostPosted: Thu Jun 27, 2013 12:16 am 
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Joined: Fri Mar 23, 2012 7:58 pm
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Thx a lot for your time answering my question! You know what, I built this gun from scratch, part by part, to learn and understand this pellet gun completly. This my fourth built, my 2 first were spring powered and my 2 last nitro piston powered. This is my best built so fare, my first was 1090fps with .22 PBA, my second 1060fps, my first nitro piston 1000fps et this one 1108fps. I never saw this plastic part until recently when I received my 2 new lever assembly. Actualy they sent me 2 without the wheel... I didn't understand. They sent me back free 2 with the wheel and actualy one of them had this little piece of plastic. Since it was the first time I saw it, I didn't thought it was important, I dropped it to the floor and it disapear after vacuum cleaning. I was thinking tha with the coking pressure, the plastic on metal would wear very fast and so there was no point. I don't know if I can order a couple from Gravel Agency since it does not have any part number. But I will, as you advise me, find an alternative of cours and still use molly grease between to lessen friction. Thx very much for the answer!

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PostPosted: Thu Jun 27, 2013 3:55 am 
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Joined: Sun Jan 29, 2012 7:31 pm
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Location: Halifax, NS
You are welcome. Yes if/when the plastic bit is on .. check it after use .. hardly any wear on it. It is not available separately as an individual part last I checked.

BTW ... does your POI change every 50 shots or so ? perhaps the screws start to come loose after 50 shots or so & you had to Loctite em ?
Do you run out of elevation ? or perhaps think you have/had barrel droop ? have you shimmed or maxed out your scope for elevation ?
I sound like an insurance commercial .. lol .. just noticed a cpl of things in yer pics & have a hunch bout something so am asking these questions in particular.

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PostPosted: Thu Jun 27, 2013 5:45 am 
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I sent an e-mail to Gravel Agency to ask them for this part. If they sent it to me (only one on four lever assembly... wich doesn't surprise since they can send lever assembly without the wheel.) If they can't I will find something to do the same job.

I can't answer your questions, I know it will sound weird and strange, but I don't understand them lol I built this gun as a challenge, I love assembling, disassembling and moding. At the begining I was target shooting in my basement but it's definitively too powerful as a gun and I made holes everywhere wich anger my mother a lot. I'm living in town and don't have anywhere else to go so I can't use it outside in my backyard. My pleasure was simply to test the fps differene between springs, nitro piston, .22 caliber vs .25 caliber. I did at first a lot of penetration test. So in fact now I'm not using it realy but I don't care, I'm just happy and proud of my build and the results! I also have a scope red laser (not installed on the picture) wich allow me to exactly know where to look in my scope sight because at 30 feets, I can't center it.

My next steps is to powder coat all the black metal parts to give it the same look as the silver Benjamin Sheridan .22 classic. After I will try to change the wood stock color to give it a synthetic black look. There no synthtetic stock available for this magnum model.


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PostPosted: Thu Jun 27, 2013 8:13 am 
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Joined: Mon Sep 05, 2005 10:55 pm
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Location: Rocky Mtn Hse Alberta
What do you mean by 'built from scratch'?


cheers,

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PostPosted: Thu Jun 27, 2013 9:22 am 
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Joined: Fri Mar 23, 2012 7:58 pm
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I first bought a Benjamin Sheridan Classic .22 that I learned to work on it, disassemble, convert spring to nitrogen piston, re-assembly. After I decided to take, legaly (Valid Pal plus registery) to order parts a couple at time and with my experience of the Classic 22 + the Crosman diagram and parts number. It's been a real challenge, mainly to find something strong enough to compress this huge spring without putting my heal at danger. Now I'm at my 4 builts and each time I'm doing it better and have better results. For me it's very important to completly learn my guns (as in the military), I need to know and understand at it work so I can easily detected a failure. Of coure I have never explain and will never explain how I did it, I don't want anybody to know such informations.

I must say that for someone that has to work with opening the cylinder and working inside that the Nitro Piston is a real marvel, it doesn't take any compression to fully enter the cylinder wich make working the cylinder without the danger of spring decompression.


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PostPosted: Thu Jun 27, 2013 11:57 am 
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Joined: Mon Sep 05, 2005 10:55 pm
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Location: Rocky Mtn Hse Alberta
So if I have that right you bought parts and assembled a Benji NP XL based on a parts list. Sounds like an expensive way to end up with a rifle. Having fun though, is priceless.

BTW the wheel is there to run on the stock. The glide is there to protect the cylinder.

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PostPosted: Thu Jun 27, 2013 12:32 pm 
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Joined: Fri Mar 23, 2012 7:58 pm
Posts: 154
I don't care much for the price, I'm used to airsoft parts that can reach so ridiculous price for nothing much. In fact it's only purpose was to learn something you, wich boost the logic of undertsanding the functionning, relation between each parts and how to develop, after each build of trial and error, the undertsanding of the physic of how works a break barrel airgun. Yes it cost me way more then buying one, but this without the fact that I have actualy the triple of each parts (spare parts), I have one spring cylinder with 2 pistons and spring. This when I realised that their is somethimes high tolerance difference between each. Since they are cheaply made in China. For the same built method, I had one time over 100fps of difference.When you buy one, you don't always realise that, for example, their are a ton of usining gunk and dirt pieces. But when you buy a barrel (I have 3, 2 .22 caliber and one .25 caliber), the first thing I learn to do was thouroughly take a lot of time and patience to actual almost perfectly clean the inner barrel. And the difference is big beacause you do not have anymore the smoke coming of the barrel. I learned to do exactly the same thing with all my cylinder(I have 3) but I learned to do a very clean job with solvant and alcool to remove the usinage gunk. I learned to clean the solvent and what ideal quantity of molly grease to put to achieve lowest friction. I also learned to use one seal for deburing the cylinder to smooth it and to put another one that would not suffer friction and wear. Etc etc. I'm not saying this for bragging or saying that I'm a super duper intellligent man... I only say that because I always love to share my passion with others evem if I know that their's always personne thinking it's stupid and judging. So cheers to the others! :)

Bye the way, I continued modding and working one the gun. I sent all the upper assembly to sand blast, poweder coating in silber and with a high gloss. 100$ fro all the uper assembly. Once it will be done, he will professionaly work on my wood stock (I don't love wood stock) tu change it with a very durable black mate finish with low gloss. He will also work on an idea formy scrathing problem and we will try something different, a simple test without excpectation, to drile a whole where the lever assembly scratch the cylinder and install a very small bearing with


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PostPosted: Thu Jun 27, 2013 12:35 pm 
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Joined: Fri Mar 23, 2012 7:58 pm
Posts: 154
With a rubber external to grip and easily roll on the cylinder. If it works well I will try improving iit buy doing a smalll track in the metal cylinder. I'm also working on a project from a machinist that usinated pieces of aluminium froma computer (CNC) to create a replica of a break barrel. I never love the bull barrel. We that's it, yes a lot of money that from most people is total waste but for me is really an investment


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PostPosted: Thu Jun 27, 2013 11:32 pm 
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Joined: Sun Jan 29, 2012 7:31 pm
Posts: 696
Location: Halifax, NS
Great if the gun is working good for you :)
If you are open to suggestions or need help ask away as there are plenty of important but basic mods for this gun that improve it all around.
I've yet to see any one of NP Xl series including mine (& on internet, pics, reviews, footage, gun shows etc.) that doesn't exhibit short comings & surprise it is always the EXACT same issues, once you see/realise the flaws they ship these out with you'll be shaking yer head...haha
A few of said imperfections are actually very obvious at just a glance on all the ones I've seen to date.
Soo much fun with this though & glad you are enjoying it too.

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PostPosted: Sat Jun 29, 2013 3:48 pm 
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Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
My NP XL100 is apart right now, as I'm converting it into a bullpup. If you'd like I can replicate the little "U" piece in brass and send it to you. PM me your address if interested.

Owen


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PostPosted: Sun Jun 30, 2013 3:42 pm 
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Joined: Sun Jan 29, 2012 7:31 pm
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Location: Halifax, NS
That plastic pc has give under strain & conforms to the OD of tube .. think maybe curve the contact point on brass bit to sit on tube ... ? not sure what hardness brass be fit for this, no expertise here on that matter (or any really lol) but gotta say makin me nervous ..

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PostPosted: Mon Jul 01, 2013 6:12 pm 
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Joined: Thu Jun 06, 2013 6:43 pm
Posts: 32
Location: Hanover, On
You may be right about it needing to be plastic. If the OP can't get the part, in plastic, then maybe brass might work. I think that I'll make this part even if the OP is not interested, to see if it's a suitable material. I may need one if the OEM part ever fails. Krytox GPL-205 will be the lubricant used, for testing this.

Owen


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PostPosted: Mon Jul 01, 2013 11:21 pm 
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Joined: Sun Jan 29, 2012 7:31 pm
Posts: 696
Location: Halifax, NS
Owen .. what about Delrin .. ?

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